Golden Shovel at the bottom of the hole game

It hasn't qualified as an Olympic event quite yet, but competitive hole digging is proving a popular sport in Japan.

The rules are simple - the team that can dig the deepest hole in half-an-hour is declared the winner - but pride is at stake, as well as the prestigious Golden Shovel for the winner of the National Championship.

The 2013 edition of the championship went to a team of pipe-layers from the south of Japan, who dug 3.5 metres to defeat more than 300 other teams.

They displaced the reigning champions of the Golden Shovel, the KOA Construction Company.

"Because we dig sewage trenches as a job, we don't have to do special practice, but we are ready to defend the Golden Shovel," KOA team member Koji Inose told the ABC before the event.